| Dy | Symbol for dysprosium. (05 Mar 2000) |
|---|---|
| dyad | A pair. Two units. Half of a tetrad (four units). What happens to bivalent (tetrad) chromosomes after the first nuclear division of meiosis. (09 Oct 1997) |
| dyad symmetry element | Dyad symmetry element bound by serum response factor to control the expression of c fos. (18 Nov 1997) |
| dyad symmetry of DNA | <molecular biology> Two areas of a DNA molecule whose base pair sequences are repeats of each other, inverted relative to each other, or are palindromes. (09 Oct 1997) |
| dyadic psychotherapy | A psychotherapeutic session involving only two persons, the therapist and the patient. Compare: group psychotherapy. Synonym: individual therapy. (05 Mar 2000) |
| dyadic symbiosis | Symbiosis between a child and one parent. (05 Mar 2000) |
| dyaks | <ethnology> The aboriginal and most numerous inhabitants of Borneo. They are partially civilized, but retain many barbarous practices. Source: Websters Dictionary (01 Mar 1998) |
| dyas | <geology> A name applied in Germany to the Permian formation, there consisting of two principal groups. Origin: L. Dyas the number two. Source: Websters Dictionary (01 Mar 1998) |
| dyclonine hydrochloride | 4'-Butoxy-3-piperidino-propiophenone hydrochloride;a topical local anaesthetic. (05 Mar 2000) |
| dydrogesterone | <chemical> (9 beta,10 alpha)-pregna-4,6-diene-3,20-dione. A synthetic progestational hormone with no androgenic or oestrogenic properties. Unlike many other progestational compounds, dydrogesterone produces no increase in temperature and does not inhibit ovulation. Pharmacological action: progestational hormones, synthetic. Chemical name: Pregna-4,6-diene-3,20-dione, (9beta,10alpha)- (12 Dec 1998) |
| dye | A stain or colouring matter; a compound consisting of chromophore and auxochrome groups attached to one or more benzene rings, its colour being due to the chromophore and its dyeing affinities to the auxochrome. Dyes are used for intravital colouration of living cells, staining tissues and microorganisms, as antiseptics and germicides, and some as stimulants of epithelial growth. For individual dye's, see the specific names. Commonly but improperly used for radiographic contrast medium. Origin: A.S. Deah, deag (05 Mar 2000) |
| dye dilution technique | Method for assessing flow through a system by injection of a known quantity of dye into the system and monitoring its concentration over time at a specific point in the system. (12 Dec 1998) |
| dye exclusion test | A test to determine cell viability in which a dilute solution of certain dyes (e.g., trypan blue, eosin Y, nigrosin, Alcian blue) is mixed with a suspension of live cells; cells that exclude dye are considered to be alive while cells that stain are considered dead; it is not always an accurate test because it indicates only the structural integrity of the cell membrane. (05 Mar 2000) |
| dye laser | <radiobiology> A type of laser in which the active material (the material which emits the laser light) is a dye. These lasers are tunable when the dye has very large molecules (such as acridine red or esculin) and the laser action takes place between the first excited and ground electronic states, because each of these states contains a broad continuum band of vibrational-rotational levels. (09 Oct 1997) |
| dye-dilution curve | Graph of the serial concentrations (dilutions) of a dye, e.g., Evans blue, following its intravascular or intracardiac injection; useful in the diagnosis of congenital cardiac shunts, measurement of cardiac output, and detection of cardiovalvular incompetence. Synonym: indicator-dilution curve. (05 Mar 2000) |